A structure of a conventional light-emitting diode is shown in FIG. 1. A light-emitting stack 110 is disposed on a substrate 130 with a bonding layer 120 in between. During package, the substrate 130 is fixed to a carrier 150 with a fixing material 140, and then the whole structure is packaged with an encapsulation resin 160. The light-emitting stack 110 is a semiconductor stack comprising a first conductivity type semiconductor layer 111, an active layer 112, and a second conductivity type semiconductor layer 113 from top to bottom in sequence. The first conductivity type semiconductor layer 111 and the second conductivity type semiconductor layer 113 are of different conductivity types. For example, the first conductivity type semiconductor layer 111 is an n-type semiconductor layer, and the second conductivity type semiconductor layer 113 is a p-type semiconductor layer. When an external power is supplied, the first conductivity type semiconductor layer 111 and the second conductivity type semiconductor layer 113 generates carriers (electrons/holes) respectively, and the carriers recombine in the active layer 112 to generate light. In addition, a first electrode 114 is set on the first conductivity type semiconductor layer 111, and a second electrode 115 is set on the second conductivity type semiconductor layer 113 to conduct the electrical current. For a light-emitting diode of this kind of structure, the light extraction depends mainly on the light extraction from the top side. As shown in the figure, the condition when the light emitted by the light-emitting stack 110 travels downward and arrives at the sidewalls of the substrate 130 is shown at the point A. Since the substrate 130 has a refractive index n=1.7 (taking a sapphire substrate for an example) and the encapsulation resin 160 has a refractive index n=1.5, according to Snell's law, when the light is incident to the surface of the encapsulation resin 160 at an angle greater than the critical angle, an TIR (Total Internal Reflection) occurs and light can't be transmitted out of the light-emitting diode as indicated by the dashed lines in the figure. It is even worse that the light is absorbed by the light-emitting diode after multiple reflections, which leads to a loss of brightness. Therefore, a light-emitting diode of this kind of structure has a poor light extraction in the sidewalls, and in addition to the affection in the brightness, the far field angle of the light is also relatively small.